1. Field of the Invention
The present invention is broadly concerned with compositions and methods for reducing offensive odors on a variety of substrates or in areas exhibiting such odors. More particularly, it is concerned with such compositions and methods wherein use is made of odor-reducing mixtures in both dried, solid, particulate form and in liquid, aqueous dispersion form comprising respective quantities of citric acid and a monovalent salt of citric acid. The compositions of the invention may be used to good effect for reducing or eliminating odors on a variety of substrates, e.g., landfill materials, municipal solid waste, garbage, human skin, cloth, or other absorbents.
2. Description of the Prior Art
It frequently occurs that the skin or clothing of people becomes contaminated with strong or offensive odors. To give but one example, work in and around gasoline stations often results in the strong smell of gasoline on the hands and clothing of workers.
Attempts at using soaps or detergents to remove offensive odors are sometimes effective to a degree, but often the odors persist despite industrious efforts to remove them. It has of course been suggested to employ strong-smelling materials containing perfume or the like to hide or mask offensive odors, but this many times is as disagreeable as the original odors themselves. Accordingly, there is a need for improved odor-reducing compositions which are gentle and easy to use, and which reduce or absorb offensive odors while leaving virtually no residual odors themselves.
Japanese Patent No. 62-139,662 discloses a granular deodorant for use in solid deodorant compositions consisting of 80-90 parts by weight of a ferrous salt, 15-5 parts by weight of citric acid and 5-15 parts by weight of a salt of citric acid. Ferrous salt is the chief constituent of the composition taught by this reference. The citric acid or citrate functions as a stabilizer to prevent oxidation of the ferrous salts. The reference also discloses use of fatty acid salts as a binding agent, but not as a cleansing agent. Moreover, only a solid form of the deodorant is disclosed, and not an aqueous dispersion form. The composition is not formulated to be nontoxic or food grade.
Japanese Patent No. 62-235,364 discloses a deodorant resin composition and articles molded from the resin containing thermoplastic resin and a deodorizing component. A deodorizing component comprised of a 10%-90% zinc compound such as citrate and 90%-10% of an aliphatic polycarboxylic acid such as citric acid is disclosed. In addition, the deodorizing resin composition masks, rather than chemically reacts with aldehydes or other producers of foul odors. This composition is not formulated to serve as a cleaning agent or to function in an aqueous dispersion. The disclosure is limited to use of a divalent zinc compound, which renders it toxic.
Japanese Patent No. 64-8972 teaches an aqueous deodorant dispersion comprised of zinc compounds and aliphatic polycarboxylic acids, such as citric acids, or their salts. The disclosure is limited to zinc compounds. As a consequence, the deodorant compound would be toxic.
Japanese Patent No. 63-161,968 discloses a deodorant composition containing an acidic substance and a ferrate material impregnated with a clay mineral containing polyvalent metal cations. The disclosure is limited to divalent compounds and does not teach a non-toxic compound product. This formulation does not include a cleansing agent or provide for an aqueous dispersion form.
U.S. Pat. No. 3,650,968 discloses a fisherman's soap composition for removing fishy odors. The composition consists of a source of citric acid, a detergent effective in an acid pH range, glycerin, and water. This reference does not teach use of a monovalent salt of citric acid.
U.S. Pat. No. 4,089,942 discloses a cosmetic deodorant composition and process which prevents the formation of odors due to bacterial decomposition of perspiration by maintaining perspiration within a pH range of 3 to 6. The deodorant composition includes a cosmetic carrier, an organic acid such as citric acid, and a salt of an organic acid. Nothing in this reference teaches a composition or method for odor absorption.
U.S. Pat. No. 4,690,772 describes sterilant compositions making use of a water soluble sterilant, a buffer, and a water soluble acid. Among the suggested acids is citric acid, whereas sodium citrate is disclosed as a possible buffering agent. In use, the compositions of this invention are formed as aqueous solutions having a pH of about 7.3, and are very dilute. It is believed that compositions of this character, because of the dilute nature thereof, would be very ineffective as odor reducers; in any event, this utility is nowhere taught or suggested in the '772 Patent.
U.S. Pat. No. 4,839,086 describes compositions useful for the regeneration of cation exchange resins typically found in water softening systems. The compositions described in this patent have been commercialized by JaCam Chemical Co. of Sterling, Kans., and include therein citric acid, a major proportion of a salt of citric acid (sodium citrate), as well as a small quantity of anti-caking agent. The prior art contains no suggestions, however, that compositions of the type described in U.S. Pat. No. 4,839,086, could be useful in the context of odor reduction.